Richard Whittle, in addition to being a regular contributor to Breaking Defense, is a senior scholar at the Wilson Center. He is writing a book on the Predator, the first armed drone. In an earlier incarnation, Rick once accompanied the late congressman Charlie Wilson to Pakistan for a visit to the Afghan mujahedeen. The Editor

The Senate Select Intelligence Committee hearing’s proximity clearly inspired the leak to NBC News a few days in advance of a Justice Department white paper detailing the administration’s legal justifications for killing known or suspected terrorists most anywhere in the world, even U.S. citizens. The white paper leak, in turn, may have helped inspire President Obama to capitulate Wednesday evening to persistent demands from committee member Ron Wyden and others that a more detailed Justice Department legal opinion on the issue be shared at least with key members of Congress.

Whatever the motivations for those developments, White House counterterrorism adviser Brennan’s hearing should serve as a wake up call for many Americans and their members of Congress.

A dozen years into the CIA’s least secret “covert operation” since Charlie Wilson’s war, there’s been precious little public debate in the United States about the practice of using armed, remotely piloted aircraft to kill known or suspected leaders of Al Qaeda and other terrorists in Pakistan and in other countries where no recognized armed conflict is underway.

Perhaps that’s partly because the CIA still declines to acknowledge its role in such targeted killings, much as it always refused to comment when the late Texas congressman Wilson was bragging to anyone who would listen in the 1980s that he had gotten the Agency to funnel weapons to mujahedeen insurgents fighting Soviets in Afghanistan. More likely, the lack of domestic debate on drone strikes reflects the fact that Americans seem to favor that method of combating terrorists by a wide margin.

A June 2012 poll by the Pew Research Center found that 62 percent of 1,011 Americans surveyed — margin of error plus or minus 3.5 percent — approved of drone strikes in “countries such as Pakistan, Yemen and Somalia.” Whether many Americans have thought much about whether the executive branch should be able to put people including U.S. citizens on a kill list without telling even Congress or the courts how those decisions are made is unclear. But in a democracy, it’s well past time to think about that.

Brennan’s hearing has given much-needed leverage to Wyden and others concerned about the secret process the Obama administration and the Bush administration before it have used to prosecute drone strikes carried out for the CIA.

The white paper leaked to NBC provided little new information on that question but could serve the cause of disclosure the same way a magnifying glass held up to the sun can cause combustion: by focusing light and heat.

“The paper itself doesn’t contain anything that’s new in the ongoing debate among academics and human rights groups,” said former West Point law professor and Marine Corps veteran Gary Solis. “What it does do, though, is focus in sixteen pages the very difficult issues that are involved in drone strikes.”

At issue, Solis noted, is only one of two types of drone strikes the United States has conducted since the Air Force first armed the Predator unmanned aerial vehicle with Hellfire missiles in 2001. “It’s often overlooked that there are two drone programs, the military’s and the CIA’s,” Solis observed.

The legality of the military using armed drones in combat operations is unquestioned, Solis said. “When you’re engaged in an armed conflict — which is not always easy to define, but clearly we are in an armed conflict with Al Qaeda and the Taliban in Afghanistan — the armed forces have the right to use deadly force,” he said. “They can kill and wound without fear of prosecution.”

Solis questions the CIA’s legal authority to be involved in drone strikes. Other sources, though, say the agency was authorized to conduct such operations in one or more classified presidential findings – secret orders for covert operations — signed by President George W. Bush after the terrorist attacks of Sept. 11, 2001. The CIA’s first drone strikes were conducted in the earliest days of the war in Afghanistan, which began Oct. 7, 2001.

The rest of the world isn’t so sanguine about that. Pew Research Group polling overseas find broad and deep disapproval of the practice, including among NATO allies — from 90 percent against in Greece to 59 percent in Germany. That, plus increasing pressure from domestic critics, appears to be one reason the Obama administration has gradually lifted the cone of silence on drone strikes over the past two years.

“We reject the notion that any discussion of these matters is to step onto a slippery slope that inevitably endangers our national security,” Brennan declared last April 30 in a speech at the Woodrow Wilson International Center for Scholars here. “Let me say it as simply as I can. Yes, in full accordance with the law, and in order to prevent terrorist attacks on the United States and to save American lives, the United States government conducts targeted strikes against specific Al Qaeda terrorists, sometimes using remotely piloted aircraft, often referred to publicly as drones.”

Brennan explained back then that the administration deemed such strikes legal under international and U.S. laws — specifically a nation’s right to self defense and the 2001 Authorization for the Use of Military Force Act, in which Congress approved military action against Al Qaeda members and their allies. Brennan also described, though vaguely, the steps taken before an individual is put on the target list.

Brennan’s Wilson Center address followed speeches elsewhere by State Department legal adviser Harold Koh, Defense Department General Counsel Jeh Johnson and Attorney General Eric Holder that addressed the topic. None, though, has fully explained what process the administration uses to compile its “kill list,” which Brennan has overseen. Major unanswered questions include what standards of evidence apply, and how a U.S. citizen targeted in secret can be accorded the constitutional right to due process of law, though Holder has said due process doesn’t require “judicial process.”

The administration’s refusal prior to the eve of Brennan’s hearing to acknowledge any right of congressional or judicial oversight of its targeting process has alarmed many observers — even those who believe the executive branch is exercising care in using drone strikes. “I’m a supporter of the CIA,” Solis said, but, “If it’s lawful, why the hell can’t we know about it in a democracy? If you are killing in our name, it seems to be we should have the right to know the criteria.”

To the frustration of Wyden and others, the administration had stubbornly refused for more than year to even acknowledge the existence of the classified Justice Department legal opinion which Obama promised to provide members of the intelligence committees just hours before Brennan’s hearing. The New York Times has described the document as justifying a September 2011 drone strike in Yemen that killed U.S. citizen Anwar al-Awlaki. The Sunni Muslim cleric, born in New Mexico, had been called an Al Qaeda propagandist before the strike but was described by White House officials after his death as “chief of external operations” for Al Qaeda. He was also said to have directly inspired an Army psychiatrist’s shooting of dozens of fellow soldiers at Fort Hood on Nov. 5, 2009, and a Nigerian man’s attempt to bring down an airliner with a bomb on Christmas Day the same year.

The Times and the American Civil Liberties Union last month lost a Freedom of Information Act lawsuit seeking to force the administration to release the Awlaki memorandum, which the newspaper has said was prepared by the Justice Department Office of Legal Counsel. The Times and the ACLU are appealing the decision.

The Justice Department white paper leaked to NBC this week was provided to Congress last summer as a substitute for the Awlaki memorandum, which Wyden and 10 other senators had demanded in a letter to the president earlier this week. It merely restates in greater detail arguments Holder laid out in a speech last March 5 at Northwestern University School of Law.

Stipulating that the document wasn’t intended to “determine the minimum requirements necessary” to make a targeted killing lawful, the white paper states that “using lethal force in a foreign country against a U.S. citizen who is a senior operational leader of Al Qaeda or an associated force” is legal under three conditions:

An “informed, high-level official of the U.S. government” has to determine that the targeted individual “poses an imminent threat of violent attack against the United States.”

Capturing the individual must be “infeasible.”

The operation has to be conducted “consistent” with the laws of war.

Holder outlined the same conditions in his speech at Northwestern. Even so, given that the Awlaki memorandum remains classified, the white paper means that Brennan’s hearing will be the most detailed open discussion yet of a policy that alarms many human rights advocates and angers many citizens of other countries.

Wyden acknowledged Tuesday in a statement on the white paper that “there will clearly be some circumstances” in which the president can legally order U.S. citizens killed. The senator added, though, that he would “continue to press the administration to provide Congress with any and all legal opinions that outline the president’s authority to use lethal force against Americans, and I will not be satisfied until I have received them.” Wyden wasn’t alone. Rep. Mike Rogers, the Michigan Republican who chairs the House Intelligence Committee, has said that while he regarded the Awlaki drone strike as justified, it was “a bit ridiculous” for the administration to withhold the memo justifying that strike from the intelligence committees.

As Wyden said in his statement, the white paper “touches on a number of important issues, but it leaves many of the most important questions about the president’s lethal authorities unanswered.”

Law of war expert Solis agreed. “The paper lays out a somewhat troubling, loose description of ‘imminent threat,'” he said, though he added that “imminent” is one of many terms in law that can never be defined in the abstract because they depend on the situation. In any event, he said Wednesday, “I’m sure that (Thursday) the senators are going to be trying to nail Brennan on that issue.”

The white paper leaves other questions unanswered as well:

Who is included in the definition of “high-level official” and thus empowered to approve a targeted killing?

What evidence is required to declare someone a “senior operational leader” of Al Qaeda or an “associated force?”

What are the standards of evidence for putting a U.S. citizen on a secret kill list, and how is that citizen’s constitutional right to due process of law actually provided?

What procedures are followed to sort through the evidence?

In his speech at the Wilson Center, Brennan recalled that, “A few months after taking office, the president traveled to the National Archives, where he discussed how national security requires a delicate balance between secrecy and transparency. He pledged to share as much information as possible with the American people ‘so that they can make informed judgments and hold us accountable.'”

Wednesday night, Obama took an important step toward living up to that pledge on the issue of drone strikes. Today, Brennan gets his chance to help.